profile: make the contextmanager object available to the callers

This will allow calling methods on the object in the code using the context
manager.

mercurial/profiling.py

@@ -160,6 +160,7 b' class profile(object):'
         self._entered = True
         if self._enabled:
             self.start()
+        return self
 
     def start(self):
         """Start profiling.
@@ -230,5 +231,5 b' def maybeprofile(ui):'
     just use a single code path for calling into code you may want to profile
     and this function determines whether to start profiling.
     """
-    with profile(ui, enabled=ui.configbool('profiling', 'enabled')):
-        yield
+    with profile(ui, enabled=ui.configbool('profiling', 'enabled')) as p:
+        yield p